NLM Bibliographic Products Available in MARC 21 Format
NLM cataloged titles correspond to those records in LocatorPlus which contain the value "AUTH" in the NLM locally-defined field 995 subfield $a AND the values "AUTH" or "CIP" in the NLM locally-defined field 999 subfield $a. [To determine if a record in LocatorPlus has been cataloged by NLM, click on the MARC VIEW tab and examine the full MARC 21 bibliographic record.]
Catfile is made available for licensees to ftp on a weekly basis. All records that were completed ("AUTHorized for distribution") or substantially revised are included in the weekly Catfile distribution. The average number of records in the Catfile weekly distribution is 1,000-1,500 records per week. In addition, the backfile of slightly more than 1,000,000 records is available to new licensees, if desired. Weekly files are kept for only 62 days, so if your subscription begins mid-year and you want to obtain all the previous updates, you need to subscribe to CatfilePlus, which is updated on a monthly basis.
Note that NLM does not include deleted records in the regular weekly distribution of records to Catfile licensees. A separate file containing only deleted records (with Leader byte 05="d") is issued once a year; licensees are notified when these files are available to ftp.
CatfilePlus includes NLM cataloging records and all monograph and monograph chapter records created by contributing collaborative partners in the fields of history of medicine, health technology assessment, space, bioethics, and population studies.
Records from all collaborative partners are integrated with NLM cataloging records created in the same timeframe and distributed in a single product. The MARC 998 and MARC 999 fields carry data pertaining to the creator of the monographic record. The 998 field is multiply-occurring so that a record 'owned' by two or more producers contains appropriate 998 tagging for each producer. The record may or may not be shared with NLM. Shared records are tagged as either cataloged and "authorized" bibliographic records, which are identifiable by the value "AUTH" in the NLM locally-defined MARC 21 field 999, or as bibliographic records for forthcoming publications containing cataloging-in-publication (CIP) data, identifiable by the value "CIP" in the NLM locally-defined MARC 21 field 999.
CatfilePlus is made available to licensees to ftp on a monthly basis. All records that were completed by NLM ("AUTHorized for distribution"), those with cataloging-in-publication information (CIP), all records substantially revised by NLM, as well as all records released by the collaborative partner organizations or substantially revised by them are included in the monthly CatfilePlus distribution.
The average number of records in the CatfilePlus monthly distribution is estimated to range from 4,000-6,000 records. In addition, the backfile of more than 1,100,000 records is available to licensees, if desired. In a major difference from the standard weekly Catfile distribution, subject headings in CatfilePlus are not recombined into the traditional subject heading string generally found in library catalogs (main heading - topical heading - form subheading - language subheading). Subject headings are distributed in separate fields as they are stored in LocatorPlus, NLM's online public access catalog, specifically in MARC 21 fields 650, 651, and 655.
Note that NLM does not include deleted records in the regular monthly distribution of records to CatfilePlus licensees. A separate file containing only deleted records (with Leader byte 05="d") is issued once a year; licensees are notified when these files are available to ftp.
Serfile contains some additional NLM indexing-related data in NLM locally-defined fields.
Serfile is made available for licensees to ftp on a monthly basis. All records for serials which were added or updated in any way during the previous month are included in the monthly Serfile distribution. The average number of records in the Serfile monthly distribution generally ranges between 1,000-3,000 records per month. In addition, the backfile of approximately 126,000 records is available to new licensees, if desired.
An alternative product, the List of Serials Indexed for Online Users (LSIOU), a subset of Serfile, is available in XML and PDF format. The LSIOU provides basic bibliographic information for only the serials from which articles are indexed with the MeSH® vocabulary and cited in MEDLINE (does not cover OLDMEDLINE titles). See http://www.nlm.nih.gov/tsd/serials/lsiou.html for more information. Please note that the LSIOU uses its own DTD which is different from the DTD used for SERFILE.
Note that NLM does not include deleted records in the regular monthly distribution of records to Serfile licensees. A separate file containing only deleted records (with Leader byte 05="d") is issued once or twice a year; licensees are notified when these files are available to ftp.
Sample NLM Data
Samples of Catfile, CatfilePlus, and Serfile in MARC 21 format are available for prospective NLM data licensees. A license agreement is not needed for sample data.
How to Lease
NLM leases Catfile, CatfilePlus and Serfile to U.S. individuals or organizations; to its formally recognized International MEDLARS Centers; and to non U.S. individuals or organizations solely for research purposes (limited to internal use with no commercial applications). For purposes of leasing NLM databases, the following criteria must be met to be considered a U.S. organization: the organization is incorporated in U.S.; the signing official is a principal in the organization who is located in the U.S. and is not simply an authorized agent; and any financial payment to the NLM is issued from an U.S. account (although there are no fees for leasing NLM databases in the foreseeable future).
Complete and return the applicable License Agreement and Intended Use Worksheet.
Alternative to Leasing
Individual records in MARC 21 format may be downloaded from LocatorPlus for personal use and a single copy of downloaded data may be redistributed.